Canon 550EX manual To set the master unit’s channel No Press the button Select, No , 2, 3, or, 101

3. Setting the Master/Slave Channel

To prevent your master unit from firing another photographer’s slave units, four channels are provided to differentiate your slave units from unrelated ones. The master unit and slave unit(s) in the same wireless flash system must be set to the same channel No.

1

2

Press the master unit’s < >

button and select M or .

•The TTL mode cannot be used with wireless flash photography.

To set the master unit’s channel No.,

press the < > button and

select .

•Pressing the <> button changes the selection in the following loop:

Flash output

		(Off)
Press the <		> or <	> button to set
3 the channel	No. (1, 2, 3, or 4).

101